The present invention relates to so-called xe2x80x9ctrailer tippers,xe2x80x9d apparatuses designed for simultaneously hoisting and tilting a trailer backward so that material in the trailer is discharged or dumped from its back end. Trailer tippers generally take the form of large, welded steel structures which include an elongate main frame for supporting a tipping platform or deck which is pivotally connected at one end thereof to the main frame, movable between a first lowered position to a second tilted or raised position. The tipping deck is dimensioned for receiving a large trailer loaded with material, such as refuse, to be dumped, and the sequence of operation is generally as follows.
The driver of a tractor-trailer rig backs the trailer onto the tipping deck when it is lowered, unhooks the trailer to leave it there and drives the tractor off. An operator (which may or may not be the driver) operates power-driven actuators connected to the tipping deck to pivot it upwardly to a tilt angle of approximately 60-70xc2x0 relative to the horizontal so that material from the trailer is discharged through its open-doored back end and dumped onto the ground at a selected dump site. Trailer tippers have found successful application for discharging loads from refuse trailers at large landfills and other refuse sites, as well as for dumping aggregate and other materials at construction and building sites and staging areas.
Examples of trailer tippers are shown in U.S. Pat. Nos. 5,080,548; 5,344,271; 5,458,451 and 6,019,568. In the ""568 patent, there is disclosed a spill gate for a trailer tipper which is connected to the rear of the tipping deck operable for being selectively positioned to engage the spill chute on the main frame when the tipping deck is tipped upwardly. The purpose of the spill gate disclosed in the ""568 patent is to direct material spilled from the trailer and accumulated on the tipping deck to the spill chute, as the deck is raised into dumping position. The spill gate design serves as a supplemental chute to guide material away from the main frame when the tipping deck is raised to the dumping position. The spill gate disclosed in the patent is a flat, nondeformable, rigid plate which is pivotally mounted at a bottom edge thereof to a cross beam at the rear of the tipping deck, and spans across the width of the spill chute. A hydraulic cylinder connected to the cross beam has its rod connected to the spill gate, and is operable for pivoting the spill gate about its pivot connection to the cross beam.
The spill gate disclosed in the ""568 patent operates to remove spillage from the tipping deck and main frame generally as follows. The tipping deck is initially positioned in its stowed or lowered position and a trailer is backed thereonto, after which the tractor is uncoupled and driven off the tipping deck. The hydraulic cylinder which operates to position the spill gate is retracted to orient the spill gate substantially vertically. As the tipping deck is pivoted upwardly, an operator must sequentially actuate the hydraulic cylinder to extend its rod so that the spill gate is pivoted about its pivot connection, in an opposite sense to the tipping deck, to engage the top of the upper end of the spill chute. As the tipping deck continues to be raised, the operator continuously extends the rod of the spill gate actuator so that the spill gate maintains a path for directing any overflow material from the tipping deck onto the spill chute.
While the spill gate construction disclosed in the ""568 patent provides an adequate way for disposing of material inadvertently built up or spilled onto the tipping deck from being subsequently spilled onto the main frame, it does require operator attention for trouble-free operation. Not only must an operator control the spill gate during raising of the tipping deck, but also must sequentially retract the spill gate from its extended position during lowering of the tipping deck. If the operator neglects to actuate the spill gate to rotate it away from the spill chute during lowering, the spill chute will be forced against the spill gate.
Because of the significant weight of the trailer and tipping deck, and because the spill chute is rigidly mounted on the main frame, the spill gate can be damaged, or in the extreme, torn away from its mounting to the tipping deck. And two operators may be necessary; one to control raising and lowering of the tipping deck about its pivotal connection to the main frame, and another simultaneously to operate the spill gate actuator for extension and retraction of the spill gate. Because the spill gate and its actuator are both pivotally connected to the tipping deck, and because movable parts such as a hydraulic rod are involved, material which has accumulated on the tipping deck can foul these components over time. Maintenance and repair of the hydraulic components and the pivot connections must be ongoing, particularly in applications where refuse is being dumped.
The present invention is directed to providing a novel shape-modifiable transition chute formed of flexible material to replace the spill gate shown in the ""568 patent and facilitate transfer of accumulated spillage from the tipping deck to the spill chute. In accordance with the present invention, the transition chute includes a flexible member connected both to the rear of the tipping deck and to the upper end of the spill chute. The flexible or shape-modifiable nature of the transition chute enables it to remain continuously connected to the tipping deck and the spill chute during all phases of pivotal movement of the tipping deck from its lowered to its raised positions.
When the tipping deck is in its stowed or lowered position, the transition chlute is partially deformed or bent to a collapsed configuration, owing to the flexible nature of its material. As the tipping deck is raised or tilted upwardly, it moves about its pivot connection to the main frame, simultaneously swinging the end of the transition chute, connected to the tipping deck, along an arcuate path. As the tipping deck finally reaches its ultimate diagonal or tilted position, relative to the ground, the shape of the flexible transition chute has expanded from its initial, partially collapsed first configuration to a second configuration, defining a substantially planar expanse which presents a smooth, inclined and somewhat resilient surface for receiving and directing material which has been spilled onto the tipping deck to be directed downwardly onto the spill chute for further egress.
The flexible or shape-modifiable nature of the transition chute enables it to be easily installed and readily maintained, as well as being retrofitted onto existing trailer tippers. If for some reason the transition chute becomes torn or otherwise damaged and needs repair or replacement, it can readily be detached and a substitute installed. The flexible nature of the transition chute also provides the additional advantage of shock absorption. As heavy and large chunks of material, such as refuse material, collide with the transition chute in its intermediate or raised positions, the transition chute may flex or give, and provides a resilient, as opposed to rigid, surface.
The shape-modifiable transition chute of the present invention may be made of readily available materials, such as rubberized conveyor belt material or rubber or vinyl belts could be used, so long as they were sufficiently thick and resilient to withstand material impact.